1. Field of the Invention
The present invention relates to a reflecting screen for observing image light (light of an image) coming from the front by reflecting the light using a reflecting surface, a method of manufacturing the reflecting screen, and a reflection-type projection system.
2. Background Art
In the past, as a reflecting screen of the type as mentioned above, one having a light transmitting diffusion layer provided on the front face side of a clear sheet and a linear Fresnel lens face for reflecting light provided on the rear face side has been known (for example, Patent Document 1). Also, Patent Document 2 discloses a construction of a reflecting screen which controls lowering of a contrast due to natural light and enables to obtain an appropriate viewing angle. Additionally, Patent Document 3 describes a reflecting screen which is composed of a combination of a lenticular lens and a linear Fresnel lens arranged orthogonally to the lenticular lens in the rear face provided with a reflecting portion.
However, there is a need for obtaining higher contrast images, and a need for obtaining images with possibly high brightness even in the case of a low amount of light of the light source on the projection side. Even though it is possible to obtain images with high brightness, elimination of unnecessary surface strong shining is always needed.
Moreover, in the conventional reflecting screens as mentioned above, the manufacturing steps are complex, resulting in increase of the manufacturing cost.
In addition, Patent Document 4 discloses a reflecting screen for observing light projected obliquely from the front by reflecting the light, in which reflecting faces and light absorbing faces are formed in a screen face with a sawtoothed cross section such that faces at which image light arrives and faces at which natural light arrives are formed separately.
However, in the case of the reflecting screen described in the Patent Document 4, it is necessary to manufacture the screen with the reflecting faces and the light absorbing faces being distinctly separated in the screen face along with a sawtoothed cross section. However, it is difficult to form a reflecting face as one side of each tooth portion separately from a light absorbing face as the other side of the tooth portion, thus raising the unit price of manufacture.
Documents Cited:
    Patent Document 1: TOKUKAIHEI No. 8-29875, KOHO    Patent Document 2: TOKUKAIHEI No. 10-62870, KOHO    Patent Document 3: TOKUKAI No. 2002-311507, KOHO    Patent Document 4: TOKUKAIHEI No. 2-262134, KOHO